An ocean sediment record reveals chaotic ocean circulation changes during warm climates Instabilities in Earth's climate system have intrigued scientists ever since analyses from Greenland ice cores revealed climate variations over the last hundred thousand years (1, 2). Abrupt changes were not singular events but a pervasive feature of the last ice age. Studies pointed to the ocean, specifically the Atlantic Meridional Overturning Circulation (AMOC), as a possible origin of these large swings (3, 4). Their occurrence in the distant past of the last ice age and their absence in the past 8000 years suggested that we are living in times of relative climate stability. On page 1485 of this issue, Galaasen et al. (5) report that over the past 500,000 years, there were disruptions in the formation of the North Atlantic Deep Water mass—an essential driver of the AMOC—during interglacial periods. This suggests that substantial reductions or instabilities of the AMOC could also occur in a future warmer climate.

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气候稳定的惊喜

海洋沉积物记录揭示了温暖气候期间海洋环流的混乱变化 自从格陵兰冰芯的分析揭示了过去十万年来的气候变化 (1, 2) 以来，地球气候系统的不稳定性引起了科学家们的兴趣。突然的变化不是单一事件，而是最后一个冰河时代的普遍特征。研究指出海洋，特别是大西洋经向翻转环流 (AMOC)，可能是这些大波动的起源 (3, 4)。它们出现在最后一个冰河时代的遥远过去，而它们在过去 8000 年中却没有出现，这表明我们生活在气候相对稳定的时代。在本期第 1485 页，Galaasen 等人。(5) 报告说，在过去的 500,000 年里，在间冰期，北大西洋深水团（AMOC 的重要驱动因素）的形成受到了干扰。这表明，在未来气候变暖的情况下，AMOC 的大幅减少或不稳定也可能发生。